From DE 10 2012 202 272 A1 a generic rotor of a supercharging device with at least two parts which are fastened to one another is known, which together enclose a hollow space. The two parts in this case are fastened to one another via subpressure that is present in the hollow space, in particular via a vacuum. The known rotor is supported via bearing bushes which are arranged alongside on the end sides.
From DE 10 2008 057 729 A1 an exhaust gas turbocharger for an internal combustion engine, in particular for a motor vehicle, is known, in which a rotor is supported in a stator. In order to be able to realise a particularly low-friction bearing, a pneumatic radial bearing is pneumatically charged by the rotor during the operation.
From DE 1 575 700 A1 a further gas-lubricated exhaust gas turbocharger is known.
Disadvantageous with known rotors for exhaust gas turbochargers is that these are usually formed by a solid shaft, which is comparatively heavy. If by contrast hollow bearing bushes for a radial air bearing are employed, these are light but also comparatively soft, as a result of which the natural frequency of the rotor in turn is disadvantageously impaired.